1. Technical Field
The present invention relates generally to data communication systems and, more specifically, to the use of wires to support data transmission in a digital data communication system.
2. Background Art and Technical Problems
A number of data communication techniques may be utilized to provide digital data to consumers at high data rates. Such digital data may be associated with telephone, facsimile machine, video, audio, Internet, and other applications. In contrast to the traditional 4 kHz bandwidth telephone transmission system, digital data transmitted with other techniques can be used to convey a large amount of information in an efficient and accurate manner. Such digital data may be transmitted at high bit rates in accordance with any number of conventional methods and protocols, e.g., cable modem technology, fiber optic networks, Digital Subscriber Line (DSL) modem technology, Integrated Services Digital Network (ISDN) technology, wireless digital modem technology, and the like.
Most customer premises are merely wired to support plain old telephone service (POTS) transmissions. In the context of this description, xe2x80x9ccustomer premisesxe2x80x9d may be a single family home, a multiple family building such as an apartment complex, an office building, or the like. For example, some conventional DSL circuits and traditional analog modems are provisioned over a single twisted pair of wires associated with a customer site. However, due to losses in the lines and crosstalk, it is often not possible to achieve data rates which the user desires over a single twisted pair circuit.
HDSL (High bit rate Digital Subscriber Line) applications often use a four wire system (i.e., two twisted pairs). Data transmission in an HDSL system is bidirectional and encoded differentially across each pair of wires, in order to achieve the desired data rates. In this respect, additional twisted pair circuits are used by bonding the circuits together in a manner called xe2x80x9cinverse multiplexing.xe2x80x9d Inverse multiplexing involves apportioning the bits between the multiple circuits (e.g., the first bit travels down the first circuit path, the second bit travels down a second circuit path, and so on). Inverse multiplexing provides a link with increased capacity, such that very high data rates may be achieved. However, for each additional circuit path, an additional twisted pair of wires is required. In addition, the telephone company tariffs are for each twisted pair, making each additional twisted pair a financial consideration. Thus, because the supply of wires is often limited in a practical consumer application, the use of inverse multiplexing to increase data rates may be limited.
Prior methods of efficient and high speed data transmission to a customer premises have not adequately leveraged the wiring and architecture common to many customer premises (e.g., POTS), or developed improved wiring and architecture to support higher speed data transmission. Thus, a technique for exploiting wiring schemes for data transmission is needed which overcomes the shortcomings of the prior art.
In accordance with one aspect of the present invention, a more efficient use of data transmission wires to a customer premises is provided. A wiring scheme for using wires for data transmission supports Nxe2x88x921 circuits for N wires. Each circuit is capable of transmitting a different signal, e.g., a DSL transmission. The wiring scheme also designates one of the N wires as a common wire for each of the Nxe2x88x921 circuits. In addition, the voltage polarities on each of the Nxe2x88x921 circuits can be reversed to reduce the likelihood of overloading of the common wire. The wiring scheme of the present invention may be used to achieve higher data rates relative to conventional schemes that do not utilize a common wire for a plurality of circuits.